<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
  <div class="demo">
    <div class="box">
        <div class="erweima"></div>
    </div>
  </div>
    <script>
        // 1.父节点 parentNode
        var erweima = document.querySelector('.erweima')
        // var  box = document.querySelector('.box')
        erweima.parentNode
        // 得到的只会是最近的父级 （亲爸）如果找不到则返回null
        console.log(erweima.parentNode);
        
    </script>
</body>
</html>